Question

When a man has an allele combination Ww for a trait, what percentage of his gametes will have a dominant allele for the trait?

Answer 1

Answer:

The correct answer is option d) 50%.

Explanation:

• Humans are diploid organisms who have 23 pairs or 46 chromosomes in their genome.
• Each pair of chromosomes can also called as a pair of alleles.
• Alleles are alternating forms of the same gene.
• Of the 46 chromosomes, 23 are obtained from the mother and rest 23 from the father.
• According to Mendel's law of dominance, the alleles can be either dominant or recessive. A dominant allele can show its character even if only a single copy of it is present in the diploid organism, while a recessive allele gets expressed only when both the allele present are recessive.
• Unlike somatic cells which are diploid, gametes are haploid, that is, they possess only one allele for one gene.
• According to Mendel's law of segregation, the allele representing each gene separate from each other during gamete formation, such that, each gamete gets a single allele representing each gene.
• The man having an allele combination Ww for a particular trait, has one dominant allele (W) and the other recessive allele (w). The gametes produced by this man will have either a dominant allele (W) or a recessive allele (w).
• Out of the two types of gametes (W and w), produced by the man, one has the dominant  allele (W).
• The ratio of dominant allele(W) containing gamete to number of gametes possible (W or w) is 1 : 2.
• Therefore, percentage of the man's gametes that will have a dominant allele is 50% (by converting the ratio into percentage).